Reduction of total acid number (TAN) of crude oil and distillate was investigated. Organic amines and aqueous ammonia were evaluated. Among organic amines, diethylamine and diethylenetriamine can effectively reduce the TAN. Superior alkalinity can improve acid removal while steric hindrance may weaken acid removal. The result showed that aqueous ammonia can acquire ideal results when the molecule ratio of ammonia to naphthenic acid reaches 3:1, the dosage of demulsifiers is 40 mg/l, the weight ratio of LA42 to LGA is 1:1 and electric strength reaches 1500 V/cm. The heat stability of the treated crude oil was tested.